Biomass-based flame retardant and preparation and application thereof

Abstract

The application discloses a biomass-based flame retardant and preparation and application thereof. The biomass-based flame retardant is prepared from raw materials of biomass, i.e. vanillin, dimethyldichlorosilane, 4,4-diaminodiphenyl methane and DOPO, and is a novel environment-friendly halogen-free flame retardant, which is non-toxic, environment-friendly, has good flame retardant performance, and has high compatibility with an epoxy resin matrix. When the biomass-based flame retardant is used for preparing a flame-retardant epoxy resin product, the obtained epoxy resin product has the characteristics of low phosphorus content, good flame retardant performance, high oxygen index and high mechanical strength.

Description

TECHNICAL FIELD

[0001] The present application relates to a flame retardant and its preparation and application, in particular to a biomass-based flame retardant and its preparation and application. BACKGROUND

[0002] Epoxy resin is one of the most common thermosetting polymers, which has excellent chemical resistance, mechanical properties and adhesion, and is widely used in many engineering fields and our daily life. However, the inherent flammability of epoxy resin hinders its practical application in many fields, and the epoxy resin releases a large amount of heat and toxic smoke when burning, which can cause death of humans and animals.

[0003] In practical applications, especially in fire-prone fields such as electronic appliances, it is necessary to reduce the fire risk of material parts by improving the flame retardant performance of epoxy resin. However, there are still many problems in the application of flame retardants in epoxy resin in the prior art:

[0004] First, halogen-based flame retardants pollute the environment;

[0005] Second, halogen-free flame retardants are not efficient enough, and compared with halogen-based flame retardants, they often need a larger amount of addition to achieve the same flame retardant grade, which will greatly affect other properties of epoxy resin, such as viscosity increase and mechanical property decrease;

[0006] Third, the existing halogen-free flame retardants usually have poor compatibility with the epoxy resin matrix, which negatively affects the mechanical strength of the epoxy resin after addition.

[0007] Therefore, it is one of the current research focuses for the technical personnel in the field to study and develop an environmentally friendly flame retardant with high flame retardant efficiency, good compatibility with epoxy resin, and excellent comprehensive performance of flame-retardant products, and its products. SUMMARY

[0008] In order to solve the above technical problems, the present application provides a biomass-based flame retardant and its preparation and application. The biomass-based flame retardant of the present application is a new type of environmentally friendly halogen-free flame retardant, which has the characteristics of non-toxicity, environmental protection, good flame retardant performance, and high compatibility with the epoxy resin matrix. When used for preparing flame-retardant epoxy resin products, the obtained epoxy resin products have the characteristics of low phosphorus content, good flame retardant performance, high oxygen index, and high mechanical strength.

[0009] One of the technical solutions of the present application is:

[0010] A biomass-based flame retardant is provided, which has the following chemical structure:

[0011]

[0012] wherein n>10.

[0013] The second technical solution of the present application is:

[0014] A preparation method of biomass-based flame retardant is provided, comprising the following steps:

[0015] S1. Vanillin and amine reagent are taken and dissolved in an organic solvent, stirred for 5-15 min under nitrogen atmosphere to obtain A liquid;

[0016] S2. Dimethyldichlorosilane is taken and dissolved in an organic solvent to obtain B liquid;

[0017] S3. B liquid is added to A liquid, stirred for 3-7 h, then the amine salt hydrochloride is removed by filtration, the solution is sequentially washed and filtered with saturated sodium chloride solution and deionized water, finally the solvent is removed by distillation, and then dried for 10-15 h to obtain white powder VDSi;

[0018] S4. VDSi is taken and dissolved in anhydrous ethanol, stirred for 20-40 min at 60-80°C under nitrogen atmosphere to obtain C liquid;

[0019] S5. 4,4-diaminodiphenylmethane is taken and dissolved in anhydrous ethanol to obtain D liquid;

[0020] S6. D liquid is added to C liquid, stirred for 5-7 h at 60-80°C to obtain E liquid;

[0021] S7. DOPO and zinc chloride are taken and dissolved in anhydrous ethanol to obtain F liquid;

[0022] S8. F liquid is added to E liquid, reacted for 10-20 h at 60-80°C, cooled to room temperature, diluted with an organic solvent, the diluted product is washed with water, the solvent is removed by distillation, and finally dried to obtain a light yellow powder solid biomass-based flame retardant.

[0023] Preferably, in the aforementioned preparation method of biomass-based flame retardant, the amine reagent in S1 is one of triethylamine, diethylamine or pyridine.

[0024] Preferably, in the aforementioned preparation method of biomass-based flame retardant, the mass ratio of vanillin and amine reagent in S1 is 1:1.

[0025] Preferably, in the aforementioned preparation method of biomass-based flame retardant, the organic solvent is one of dichloromethane, ethyl acetate, tetrahydrofuran or n-hexane.

[0026] Preferably, in the aforementioned preparation method of biomass-based flame retardant, the mass ratio of the amounts of vanillin, dimethyldichlorosilane, 4,4-diaminodiphenylmethane and DOPO is 12-18:3-9:5-11:11-17.

[0027] Preferably, the biomass-based flame retardant preparation method, the mass ratio of DOPO and zinc chloride in S7 is 142:3-5.

[0028] The third technical solution of the present application is:

[0029] The biomass-based flame retardant is applied in the flame-retardant epoxy resin.

[0030] The fourth technical solution of the present application is:

[0031] The flame-retardant epoxy resin comprises the biomass-based flame retardant in the first solution.

[0032] Preferably, the flame-retardant epoxy resin comprises 100 parts of an epoxy resin matrix, 2-8 parts of the biomass-based flame retardant and 10-25 parts of a curing agent by weight.

[0033] The beneficial effects of the present application are:

[0034] 1. The biomass-based flame retardant is a new type of polymer flame retardant.

[0035] 2. The biomass-based flame retardant is prepared by using biomass-based vanillin as the main raw material, and the obtained flame retardant product is a halogen-free flame retardant, which has the advantages of non-toxicity and environmental protection.

[0036] 3. The biomass-based flame retardant has Si, P and N flame-retardant components in the structure, has good flame-retardant performance, and has a smaller addition amount and smaller influence on the mechanical properties and mechanical strength of the epoxy resin matrix under the condition of the same flame-retardant grade. Through experiments, the flame retardant has good flame-retardant performance when the phosphorus content is as low as 0.64%.

[0037] 4. The biomass-based flame retardant has better compatibility with the epoxy resin matrix and higher oxygen content, and can further improve the oxygen index of the epoxy resin. Through experiments, the oxygen index of the epoxy resin added with the flame retardant of the present application is as high as 34.3%, which is increased by 42.9% compared with pure epoxy resin.

[0038] 5. The biomass-based flame retardant uses 4,4-diaminodiphenyl methane and dimethyldichlorosilane as raw materials, so that there is a flexible chain in the chemical structure of the flame retardant, and therefore the mechanical strength of the flame-retardant epoxy resin after addition is higher. Through experiments, the UL-94 grade of the epoxy resin using the flame retardant of the present application is V0, the bending strength is increased by 30% compared with pure epoxy resin, and the impact strength is increased by 171.43% compared with pure epoxy resin. BRIEF DESCRIPTION OF DRAWINGS

[0039] ATTACHMENT Figure 1The image shows a comparison of the infrared spectra of the flame retardant VDSINP of the present invention and the raw materials DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), VAN (vanillin), and the intermediate product VDSI during the preparation process.

[0040] from Figure 1 It can be seen that in the vanillin spectrum, at 3158 cm⁻¹ -1 and 1661cm -1 The absorption peaks appearing at 2439 cm⁻¹ belong to the characteristic peaks of the -OH and C=O stretching vibrations, respectively. -1 The absorption peak is a characteristic peak of the PH bond on DOPO. In the VDSI spectrum, the characteristic peak of the -OH stretching vibration disappears, and the peak at 1100 cm⁻¹ disappears. -1 The characteristic peak of the Si-OC bond appears at 3357 cm⁻¹. In the VDSINP spectrum, the characteristic peaks of C=O stretching vibration and PH bond are both absent, while the characteristic peak of the PH bond disappears at 3357 cm⁻¹. -1 and 3463cm -1 (NH stretching vibration), 1511cm -1 (PC key), 1286cm -1 (CN key), 1183cm -1 (P=O bond) and 1030cm -1 The presence of a characteristic peak at the (PO bond) indicates that a related chemical reaction has occurred.

[0041] Infrared spectroscopy can prove that relevant chemical reactions occurred between the raw materials, indirectly proving the successful synthesis of VDSINP.

[0042] Appendix Figure 2 The NMR spectrum of the flame retardant of this invention;

[0043] from Figure 2 It can be seen that the PH bond signal of the target product VDSiNP,DOPO is in its 1 The peaks disappeared in the H-NMR curve, and some new peaks appeared. For example, the peak at 4.53-4.62 ppm represents the H on the benzene ring linked to the phospholipid phenanthrene structure, and the peak at 8.69 ppm represents the NH bond. These results indicate that the Schiff base reaction occurs between 4,40-diaminodiphenylmethane and VDSi, followed by nucleophilic addition between DOPO and the Schiff base structure, further demonstrating the success of the synthesis reaction.

[0044] Appendix Figure 3 Impact performance of EP / VDSiNP composite materials using the flame retardant of this invention. Detailed Implementation

[0045] The application will be further described in connection with the following examples, but not as a basis for limiting the application.

[0046] Embodiment of the application

[0047] The reaction path of the flame retardant of the embodiment of the application in the synthesis process is as follows:

[0048]

[0049] Example 1

[0050] The embodiment of the application is a biomass-based flame retardant, and the preparation method is as follows:

[0051] (1) 15.2 g of vanillin and 15.2 g of triethylamine reagent were taken and dissolved in a dichloromethane solution, and then placed in a three-necked flask, and stirred for 10 min under a nitrogen atmosphere;

[0052] (2) 6.45 g of dimethyldichlorosilane was taken, dissolved in a dichloromethane solution, and then dropped into the three-necked flask of (1), and stirred for 4 h, and then the generated amine hydrochloride salt was removed by filtration, and the solution was sequentially washed and filtered with saturated sodium chloride solution and deionized water, and finally the solvent was removed by rotary evaporation, and dried in a drying box for 12 h to obtain a white powder substance (VDSi);

[0053] (3) VDSi was dissolved in anhydrous ethanol, and then placed in a three-necked flask, and stirred for 0.5 h at 70°C under a nitrogen atmosphere;

[0054] (4) 8.2 g of 4,4-diaminodiphenylmethane (DDM) was taken, dissolved in anhydrous ethanol, and then dropped into the three-necked flask of (3), and stirred for 6 h at 70°C under magnetic stirring;

[0055] (5) 14.27 g of DOPO and 0.4 g of zinc chloride were taken, dissolved in anhydrous ethanol, and then dropped into the three-necked flask of (3) at 70°C, and reacted for 14 h, after the reaction, the polymer was diluted with dichloromethane solution, and the obtained mixture was washed with deionized water, and then the solvent was removed by rotary evaporation, and finally dried in a vacuum drying box for 12 h to obtain a light yellow powder solid biomass-based flame retardant VDSINP.

[0056] Example 2

[0057] The embodiment of the application is a flame-retardant epoxy resin, which is prepared by the following method:

[0058] (1) 30 g of the flame retardant of Example 1 and 1000 g of epoxy resin were mixed, and then stirred at 150°C until transparent liquid was obtained, thereby obtaining a flame-retardant epoxy resin;

[0059] (2) The flame-retardant modified epoxy resin of (1) is poured into a mold with 250 g of a curing agent while hot, and cured at 120°C / 2h and 160°C / 2h, to obtain a cured flame-retardant epoxy resin.

[0060] The cured flame-retardant epoxy resin obtained in this example has an oxygen index of 28.9%, a flame-retardant rating of V1, a bending strength of 90.42 MPa, a bending modulus of 2377.55 MPa, and an impact strength of 15.58 kJ / m 2 .

[0061] Example 3

[0062] This example is a flame-retardant epoxy resin, which is prepared by the following method:

[0063] (1) 60 g of the flame retardant of Example 1 and 1000 g of an epoxy resin are mixed and stirred at 150°C until transparent liquid is obtained, to obtain a flame-retardant epoxy resin;

[0064] (2) The flame-retardant modified epoxy resin of (1) is poured into a mold with 250 g of a curing agent while hot, and cured at 120°C / 2h and 160°C / 2h, to obtain a cured flame-retardant epoxy resin.

[0065] The cured flame-retardant epoxy resin obtained in this example has an oxygen index of 32.1%, a flame-retardant rating of V1, a bending strength of 109.84 MPa, a bending modulus of 2763.34 MPa, and an impact strength of 18.62 kJ / m 2 .

[0066] Example 4

[0067] This example is a flame-retardant epoxy resin, which is prepared by the following method:

[0068] (1) 90 g of the flame retardant of Example 1 and 1000 g of an epoxy resin are mixed and stirred at 150°C until transparent liquid is obtained, to obtain a flame-retardant epoxy resin;

[0069] (2) The flame-retardant modified epoxy resin of (1) is poured into a mold with 250 g of a curing agent while hot, and cured at 120°C / 2h and 160°C / 2h, to obtain a cured flame-retardant epoxy resin.

[0070] The cured flame-retardant epoxy resin obtained in this example has an oxygen index of 34.3%, a flame-retardant rating of V0, a bending strength of 111.24 MPa, a bending modulus of 3018.46 MPa, and an impact strength of 18.41 kJ / m 2 .

[0071] Example 5

[0072] This example is a pure epoxy resin, which is prepared by the following method:

[0073] (1) Take 250 g of curing agent and 1000 g of epoxy resin, pour into the mold while hot, 120°C / 2h, 160°C / 2h temperature rise curing, get cured pure epoxy resin.

[0074] The oxygen index of the cured pure epoxy resin prepared in this example is 24%, the flame retardant grade is none, the bending strength is 85.6 MPa, the bending modulus is 1756 MPa, and the impact strength is 6.86 kJ / m 2 .

[0075] The flame retardant performance test results of the epoxy resin materials of examples 2-5 are shown in table 1 as follows:

[0076] Table 1

[0077] Name UL-94 LOI (%) EP - 24 EP / VDSINP3 V1 28.9 EP / VDSINP6 V0 32.1 EP / VDSINP9 V0 34.3

[0078] Wherein EP item is the pure epoxy resin sample of example 5, EP / VDSINP3, EP / VDSINP6 and EP / VDSINP9 items correspond to the epoxy resin composite materials prepared in examples 2-4 respectively.

[0079] Example 6

[0080] This example is a kind of biomass-based flame retardant, and its preparation method is as follows:

[0081] (1) take 12g of vanillin and 12g of diethylamine reagent, dissolve in ethyl acetate solution and place in a three-necked flask, stir for 5min under nitrogen atmosphere;

[0082] (2) take 3g of dimethyl dichlorosilane, dissolve in ethyl acetate solution and drop into the three-necked flask of (1), stir for 3h, then remove the generated amine hydrochloride by filtration, and then wash and filter with saturated sodium chloride solution and deionized water, finally remove the solvent by rotary evaporation and dry in a drying oven for 10h to obtain white powder (VDSi);

[0083] (3) dissolve VDSi in anhydrous ethanol, then place in a three-necked flask, stir for 20min under nitrogen atmosphere at 60°C;

[0084] (4) take 5g of 4,4-diaminodiphenylmethane (DDM), dissolve in anhydrous ethanol, and drop into the three-necked flask of (3), stir for 5h at 60°C;

[0085] (5) Take 11 g of DOPO and 0.3 g of zinc chloride, dissolve in anhydrous ethanol, drop into the three-necked flask of (3) at 60°C for 10 h, after reaction, cool to room temperature, dilute the polymer with ethyl acetate solution, wash the obtained mixture with deionized water, then remove the solvent by rotary distillation, finally dry in a vacuum drying oven for 12 h to obtain a light yellow powder solid biomass-based flame retardant VDSINP.

[0086] Example 7

[0087] This embodiment is a biomass-based flame retardant, and the preparation method is as follows:

[0088] (1) Take 18 g of vanillin and 18 g of pyridine reagent, dissolve in n-hexane solution, and place in a three-necked flask, stir for 15 min under nitrogen atmosphere;

[0089] (2) Take 9 g of dimethyl dichlorosilane, dissolve in n-hexane solution, and drop into the three-necked flask of (1), stir for 7 h, then filter to remove the generated amine hydrochloride salt, wash the solution with saturated sodium chloride solution and deionized water in turn, and filter, finally remove the solvent by rotary distillation, and dry in a drying oven for 10 h to obtain a white powder substance (VDSi);

[0090] (3) Dissolve VDSi in anhydrous ethanol, then place in a three-necked flask, stir at 80°C for 40 min under nitrogen atmosphere;

[0091] (4) Take 11 g of 4,4-diaminodiphenyl methane (DDM), dissolve in anhydrous ethanol, and drop into the three-necked flask of (3), stir at 80°C for 7 h;

[0092] (5) Take 17 g of DOPO and 0.5 g of zinc chloride, dissolve in anhydrous ethanol, drop into the three-necked flask of (3) at 80°C for 20 h, after reaction, cool to room temperature, dilute the polymer with n-hexane solution, wash the obtained mixture with deionized water, then remove the solvent by rotary distillation, finally dry in a vacuum drying oven for 12 h to obtain a light yellow powder solid biomass-based flame retardant VDSINP.

[0093] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A biomass-based flame retardant, characterized by, The chemical structural formula is as follows: ； Wherein, n>10.

2. A process for the preparation of a biomass-based flame retardant according to claim 1, characterized in that, The method comprises the following steps: S1. Take vanillin and triethylamine or vanillin and pyridine, and dissolve them in an organic solvent, and stir for 5-15 min under a nitrogen atmosphere to obtain A liquid; S2. Take dimethyldichlorosilane, and dissolve it in an organic solvent to obtain B liquid; S3. Add B liquid to A liquid, and stir for 3-7 h, then remove the amine hydrochloride salt by filtration, and then sequentially wash and filter the solution with saturated sodium chloride solution and deionized water, finally remove the solvent by distillation, and then dry for 10-15 h to obtain white powder VDSi; S4. Take VDSi, and dissolve it in anhydrous ethanol, and stir for 20-40 min under a nitrogen atmosphere at 60-80 DEG C to obtain C liquid; S5. Take 4, 4-diaminodiphenyl methane, and dissolve it in anhydrous ethanol to obtain D liquid; S6. Add D liquid to C liquid, and stir for 5-7 h at 60-80 DEG C to obtain E liquid; S7. Take DOPO and zinc chloride, and dissolve them in anhydrous ethanol to obtain F liquid; S8. Add F liquid to E liquid, and react for 10-20 h at 60-80 DEG C, then cool to room temperature, dilute with an organic solvent, wash the dilution with water, remove the solvent by distillation, and finally dry to obtain a light yellow powder solid biomass-based flame retardant.

3. The process for the preparation of biomass-based flame retardants according to claim 2, characterized by the fact that: The mass ratio of vanillin to amine reagent in S1 is 1:

1.

4. The process for the preparation of biomass based flame retardant as claimed in claim 2, wherein: The organic solvent is one of dichloromethane, ethyl acetate, tetrahydrofuran or n-hexane.

5. The process for the preparation of biomass based flame retardant as claimed in claim 2, wherein: The mass ratio of vanillin, dimethyldichlorosilane, 4, 4-diaminodiphenyl methane and DOPO is 12-18:3-9:5-11:11-17.

6. The process for the preparation of biomass based flame retardant as claimed in claim 2, wherein: The mass ratio of DOPO to zinc chloride in S7 is 142:3-5.

7. Application of the biomass-based flame retardant according to claim 1 in a flame-retardant epoxy resin.

8. A flame-retardant epoxy resin, characterized by: The biomass-based flame retardant according to claim 1 is contained.

9. The flame-retardant epoxy resin according to claim 8, characterized in that: The method comprises 100 parts of an epoxy resin matrix, 2-8 parts of the biomass-based flame retardant and 10-25 parts of a curing agent by weight.

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